This invention relates to an improved method of making matt diffusion patterns, in particular to methods of making matt diffusion patterns along with opaque and transparent patterns. Such diffusion patterns are utilized, for example, in photographic camera view-finders, and on theodolite grid plates.
Hitherto, matt diffusion patterns have been made by applying the desired pattern in the form of an opaque layer to a ground glass pattern carrier plate. This process has not produced completely satisfactory results, however, because holes have tended to form in the opaque areas and thus to produce imperfect patterns. Also, this means of producing patterns has the limitation that only matt and opaque patterns can be produced thereby on a single carrier plate.